1. Field of the Invention
The present invention relates to a gas valve having automatically blocking means, and more particularly, to a gas valve having automatically blocking means, which can automatically block a supply of gas according to a change in pressure at the time of a gas leak.
2. Background Art
In general, a gas valve is mounted in the middle of a gas pipe and serves just to control a supply of gas, and hence, gas blocking means must be mounted at the gas pipe in order to automatically block the supply of gas at the time of a gas leak.
FIG. 1 shows means for blocking a supply of gas at the time of a gas leak according to a prior art.
As shown in FIG. 1, a weight 3 is mounted inside a case 5 by means of wing portions 4 having holes so as to block an inlet 1 and an outlet 2 according to gas pressure. In a normal condition, the weight 3 is located at a position to open the inlet 1 and the outlet 2, but when the gas pressure of the outlet side lowers due to a gas leak, the weight 3 blocks the outlet 1.
However, such an automatically blocking means for the gas valve according to the prior art has a problem in that it requires an auxiliary gas pipe 6 mounted at the outlet 2 for supplying gas and an electromagnet 7 mounted at the inlet 1 in order to return the weight 3 to its original position after coping with the gas leak.
In the meantime, a method of preventing a gas leak by an electromagnetic valve operated by a sensing signal of a gas sensor has been proposed, but the preventing method has a problem in that the gas sensor cannot sense a gas microleakage or cannot sense the gas leak during the blackout.